Rhinoorbital mucormycosis secondary to Rhizopus oryzae: a case report and literature review

Ear, Nose & Throat Journal, August, 2004 by Ali A. Hilal, Saad J. Taj-Aldeen, Abdulla H. Mirghani

Abstract

Mucormycosis is a form of fulminant invasive fungal infection of the sinonasal tract that often extends to the orbit, brain, palate, ands kin. It is caused by members of the order Mucorales, and it is considered to be the most fatal fungal infection known to man because it is rapidly disseminated by the blood vessels. It is most commonly associated with diabetic ketoacidosis, hematologic malignancies, acquired immunodeficiency syndrome, and immunosuppressive therapy. This rare opportunistic infection exists in many forms, the most common of which is rhinocerebral mucormycosis. Treatment includes aggressive surgical debridement of the necrotic tissue combined with systemic antifungal therapy. In this case report, we describe the successful management of rhinoorbital mucormycosis, a subtype of the rhinocerebral variety, secondary to Rhizopus oryzae that developed in a patient with lymphoma. We review the diagnostic work-up and discuss the literature with respect to the presentation, pathophysiology, management, and outcome of the disease.

Introduction

At least four forms of fungal infection of the sinonasal tract have been recognized. Two are noninvasive: allergic fungal rhinosinusitis and fungus ball (mycetoma). The other two are tissue-invasive: chronic invasive (indolent) fungal sinusitis and acute invasive (fulminant) fungal sinusitis.

One form of acute invasive sinusitis caused by fungi of the order Mucorales is known as mucormycosis. (1) Mucormycosis is a rapidly progressive infection that usually develops in patients who are metabolically or immunologically compromised. Left untreated, it is rapidly fatal. Mucormycosis classically involves the nasal mucosa with invasion of the sinuses, orbit, and brain. (2) The causative organisms are members of the family Mucoraceae, which belongs to the order Mucorales of the class Zygomycetes. They are saprophytes commonly found in soil, decomposed vegetation, and in the healthy human respiratory and digestive tracts, and their distribution is worldwide. (3)

Mucormycosis can manifest as one of six different clinical syndromes; it appears in rhinocerebral, pulmonary, gastrointestinal, central nervous system, subcutaneous, and disseminated forms. Rhinocerebral mucormycosis (RCM) is the most common of these forms, and it is subdivided into three subtypes: rhinomaxillary, rhinoorbital, and rhinoorbitocerebral. (4,5) The classification of RCM has no effect on patient care, however, because the mainstays of therapy are similar regardless of the site of extension. The keys to management are reversal of the underlying cause of immunocompromise, be it diabetic ketoacidosis or neutropenia, and appropriate antifungal therapy and surgical debridement of the involved tissues. (3-7)

Patients usually present with headache, rhinorrhea, or epistaxis along with black nasal or oral masses. Anesthesia precedes the development of the characteristic tissue necrosis. (8) Progression can lead to orbital cellulitis, orbital apex syndrome, cavernous sinus thrombosis, and eventually fatal involvement of the central nervous system. The diagnosis is made histologically because it is invasion and tissue reaction rather than the mere presence of such ubiquitous fungi that characterizes the disease. Culture is used to identify the specific species. (4)

In this article, we describe a classic presentation of rhinoorbital mucormycosis. This case illustrates the importance of maintaining a high index of suspicion in making an early diagnosis.

Case report

A 51-year-old man presented to the hematology/oncology unit with fever and generalized lymphadenopathy of 1 month's duration. He had been diagnosed with non-Hodgkin's lymphoma that had transformed into acute lymphoblastic leukemia, for which he was placed on a chemotherapeutic regimen. After 1 week of chemotherapy, the patient developed severe neutropenia with fever, mucositis, and generalized lassitude, which necessitated intravenous broad-spectrum antibiotic therapy as well as empiric antifungal treatment with fluconazole.

After a few days of this treatment in the medical ward, the patient began to exhibit recurrent mild left-sided nasal bleeding, left facial edema, excessive lacrimation from the left eye, and periorbital swelling. An ophthalmologist who was consulted noticed mild proptosis with edematous, congested conjunctiva and ophthalmoplegia; however, the eye fundus and vision were normal. A preliminary diagnosis of orbital cellulitis was made, and urgent computed tomography (CT) was requested. CT showed partial opacification of the left maxillary, ethmoid, and frontal sinuses with nasal mucosal swelling and an obvious extension of the inflammatory process to the inferomedial orbital wall, which displaced the globe anterolaterally (figure 1). But no clear collection or bony erosion was noticed, and the brain was intact. Further examination by an otolaryngologist revealed that the most striking feature of this disease was the presence of black necrotic tissue (eschar) in the left nasal cavity and a patchy black discoloration of the hard palate in two areas, each 5 mm in diameter, opposite the molars (figure 2). No ulceration was evident.